Webster's 1828 Dictionary
METONIC CYCLE, METONIC YEAR
the cycle of the moon, or period of nineteen years, in which the lunations of the moon return to the same days of the month; so called from its discoverer Meton the Athenian.
Webster's 1913 Dictionary
METONIC
Me *ton "ic, a. Etym: [Cf. F. métonique.]
Defn: Pertaining to, or discovered by, Meton, the Athenian. Metonic cycle or year. (Astron.) See under Cycle.
New American Oxford Dictionary
Metonic cycle
Me ton ic cy cle |meˈtänik mɛˌtɑnɪk ˈsaɪkəl | ▶noun a period of 19 years (235 lunar months ), after which the new and full moons return to the same days of the year. It was the basis of the ancient Greek calendar and is still used for calculating movable feasts such as Easter. ORIGIN named after Metōn, an Athenian astronomer of the 5th cent. bc .
Oxford Dictionary
Metonic cycle
Metonic cycle |mɪˈtɒnɪk | ▶noun a period of 19 years (235 lunar months ), after which the new and full moons return to the same day of the year. It was the basis of the ancient Greek calendar, and is still used for calculating movable feasts such as Easter. ORIGIN named after Metōn, an Athenian astronomer of the 5th cent. bc .
The Wordsmith Dictionary